Illumination systems typically include a light source and illumination optics for transferring light from the light source to a desired destination. Illumination systems are employed in various applications, such as projection displays and backlights for liquid crystal displays (LCD). The light source in an illumination system may, for example, include an arc lamp such as a mercury arc lamp, an incandescent lamp, a fluorescent lamp, a light emitting diode (LED), or a laser.
Projection systems typically include an active light valve for producing an image, an illumination system for illuminating the light valve, and optics for projecting and displaying the image typically on a projection screen. The illumination system in a projection system typically uses one or more white light sources, such as arc lamps. The illumination optics of the illumination system may include means for separating the white light into different colors, such as red, green, and blue.
It is often desirable to illuminate the light valve in such a way so as to display a projected image with high brightness, resolution and contrast.